“The Fifth Amendment says all sorts of things but it specifically exempts the military in a combat situation from having to adhere to it.”
yes:
“except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger..”
POTUS is the Commander of the armed services. This is a time of War or public danger. POTUS gave the order.
case closed.
That would be totally bizarre.